int main()
{
long n,k;
scanf("%ld\n",&n);
long a[n];
for(long i= 0;i<n;i++)
scanf("%ld\n",&a[i]);
for(long i=0;i<n;i++)
{
k=0;
for(long j=3;j<a[i];j++)
if(j%3==0 || j%5==0)
k=k+j;
if(k>0)
printf("%ld\n",k);
else
printf("%ld\n",k);
}
return 0;
}
Is it for https://www.hackerrank.com/contests/projecteuler/challenges/euler001 ?
The code has to be corrected first since it does not read input properly. You need to remove \n from the scanf calls.
Secondly, there are a lot of references on the net how to solve problem #1 of Project Euler. See for example https://www.mathblog.dk/project-euler-problem-1/